Access barring is a known operation in mobile networks whereby devices attempting to gain access to a network are barred from using network resources so that other devices can be allowed access to prevent congestion and to control access to limited network resources.
Currently 3rd Generation Partnership Project (3GPP) defines access control mechanisms to handle congestion conditions in a cell of a telecommunications network. A set of access control parameters are defined by 3GPP as a way to inform the wireless device, i.e., user equipment (UE), of the congestion levels in the cell. The access control parameters pertain to least two types of traffic (signaling and data), and different types of services including multimedia, telephony voice and video, for example.
To manage congestion levels in a cell of a telecommunications network, 3GPP utilizes an access control barring factor and an access control barring time, which are communicated to a UE. The barring factor, also known as the “ac-BarringFactor” is a number between 0.00 and 1.00 that indicates a point of reference that the UE should use when executing the network access procedures. Of note, 3GPP defines several sets of barring factor and barring time combinations for various types of traffic and services, for example multimedia telephony service (MMTel) video signaling, MMTel video data, MMTel voice signaling, MMTel voice data, all other signaling, e.g., access class barring (ACB) signaling, and all other data traffic, e.g., ACB data. There may be a set of barring factor and barring time combinations for each access type for every time period.
In accordance with current 3GPP standards, for each access type, a base station supporting a cell advertises an ac-BarringConfig parameter that includes the ac-BarringFactor, the ac-BarringTime and ac-BarringForSpecialAC in which:                ac-BarringFactor is taken from the set {p00, p05, p10, p15, p20, p25, p30, p40, p50, p60, p70, p75, p80, p85, p90, p95};        ac-BarringTime is taken from the set {s4, s8, s16, s32, s64, s128, s256 and s512}; and        ac-BarringForSpecialAC is a 5 bit string.        
The network access procedure includes generating, by the UE, a random number. The generated random number is compared against the barring factor, e.g., ac-BarringFactor and, if the random number is less than the barring factor e.g., as the ac-BarringFactor defined in the current TS 36.331 standard, the UE is granted access. If, however, the random number is greater than or equal to the random number, the UE must wait, i.e., is barred from retrying, for at least the specified barring time. Once the barring time has expired, the UE can once again attempt to access the cell of the telecommunication network by performing the network access procedures.
Currently, the network access procedures defined by 3GPP do not define how access control parameters are derived. In other words, the current 3GPP standard only sets out a generalized access control procedure without regard for actual resource usage and availability.